The advent of large, powerful computing devices on a single integrated circuit chip and the need to reduce their power consumption (e.g., in mobile devices) has led to the need for multiple on-chip power sources to provide a range of relatively high power supply voltages to various faster, higher-performance portions of the chip and a range of relatively low power supply voltages to various slower, lower performance portions of the chip. For example, circuitry in one part of the chip may need to operate very fast, and this may be accomplished by increasing the power supply voltage for that part of the chip while the power supply voltage(s) are much lower on slower parts of the chip. Unfortunately, adding a large number of DC-DC converters to provide different power supply voltages in various parts of the chip usually is not practical because that has required adding a corresponding number of external inductors and capacitors and associated package leads, which is very costly.